Rational Design and Synthesis of a Nanostructured Electrochemical Reactor for Alkaline Hydrogen Evolution Reaction...

Green hydrogen production driven by intermittent renewable energy poses significant challenges to alkaline hydrogen evolution reaction (HER) in achieving high-efficiency and durability. An all-in-one nanostructured electrochemical reactor (NER) was newly designed and synthesized for the HER electrode to tackle the challenges by enabling continuous electron transport and intensified gas-liquid transport in NER, thereby maximizing the interfacial charge-transfer reaction capability of the catalyst electrode under large and varying currents. This was realized by designing an all-in-one catalyst P-CoPt₃/P-CoMoO₄, featuring a self-supported structure, a heterostructure, and a super-hydrophilic nanoarray. This all-in-one catalyst functions as a built-in NER with finely-tailored critical interfaces. Self-supported structure and heterostructure form strong couplings at electron-conducting heterointerfaces, enabling continuous electron transport across these interfaces and thus in the NER. Super-hydrophilic nanoarray allows continuous gas-liquid transport at electrode/electrolyte interfaces, intensifying the gas-liquid transport process in the NER. Consequently, P-CoPt₃/P-CoMoO₄ displayed a >30-fold increase in mass activity for alkaline HER compared to the P-CoPt₃ catalyst electrode. It exhibited an impressively low overpotential of 132 mV at 1 A cm^-2. Stable operation for over 750 h at 100 and 500 mA cm^-2 and notable durability under varying currents were also obtained. Overall water-splitting of P-CoPt₃/P-CoMoO₄ || RuO₂ outperformed the commercial Pt/C || RuO_2, especially at higher currents.